17 mars 2025
Amiens - UFR des Sciences
Fuseau horaire Europe/Paris

A class of nonlinear acceleration techniques based on Krylov subspaces

17 mars 2025, 10:10
50m
Sophie Germain (Amiens - UFR des Sciences)

Sophie Germain

Amiens - UFR des Sciences

33, rue Saint-Leu, 80039 AMIENS

Orateur

Yousef Saad

Description

There has been a surge of interest in recent years in general-purpose
acceleration' methods that take a sequence of vectors converging to the limit of a fixed point iteration, and produce from it a faster converging sequence. A prototype of these methods that attracted much attention recently is the Anderson Acceleration (AA) procedure. We introduce the nonlinear Truncated Generalized Conjugate Residual (nlTGCR) algorithm, an alternative to AA which is designed from a careful adaptation of the Conjugate Residual method for solving linear systems of equations to the nonlinear context. The various links between nlTGCR and inexact Newton, quasi-Newton, and multisecant methods are exploited to build a method that has strong global convergence properties and that can also exploit symmetry when applicable. Taking this algorithm as a starting point we explore a number of other acceleration procedures including a short-term (symmetric') version of Anderson Acceleration which we call Anderson
Acceleration with Truncated Gram-Schmidt.

Documents de présentation

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